Skin is an organ carrying out functions such as protection, barrier, temperature controlling, excretion and respiration, and is composed of epidermis, dermis, and subcutaneous fat. Epidermis is the thinnest layer and is an organized construction of keratinocytes and melanocytes. Dermis is a layer that makes up approximately 95% of the skin and functions to moisturize and protect the skin. In the dermis, collagen and elastin that play an important role in skin elasticity (wrinkle) are distributed to form a net-like structure, blood vessels and nerves are found, and mast cells involved in allergic reaction and natural moisturizing factors such as Na-PCA or hyaluronic acid are also included. Subcutaneous fat functions to provide nutrients for the epidermis and dermis, determine the body shape, maintain body temperature, absorb external impacts, and protect cells under the subcutaneous fat.
The skin aging occurs with time because of rapid reduction of skin functions due to endogenous or exogenous factors. With skin aging, the epidermis, dermis, and subcutaneous fat that are components of the skin become thin, and collagen and elastin also become thin and loose and begin to lose their elasticity, causing wrinkles. Also, aging or UV exposure of skin inhibits adipogenesis in subcutaneous adipocytes, leading to loss of skin's protective function and rapid skin aging. Therefore, the tissues of face, breast and hip become droopy and wrinkle development occurs, eventually fail to have the beauty of appearance.
Many studies have been made to improve the reduced skin function, and the most important method is to find a method of promoting collagen biosynthesis of skin cells. To achieve this, vitamin C and derivatives thereof, KTTKS peptide (SEQ ID NO. 1), copper peptide and various natural extracts have been selected and used. However, vitamin C and derivatives thereof have disadvantages of a low stability and a low long-term activity, and KTTKS peptide (SEQ ID NO. 1) and copper peptide have a disadvantage of having a low collagen biosynthesis-promoting effect. The natural extracts have disadvantages of low activity and difference in their activity at the time of sample preparation. Accordingly, there is an urgent need to develop a new concept material for promoting collagen biosynthesis in order to solve all the disadvantages.